CAVIN1 and cardiac arrhythmia: Patients with CGL4 exhibit a near-total absence of metabolic fat in the subcutaneous, abdominal, and thoracic regions, with preserved mechanical and bone marrow fat. CGL4 should be suspected in the presence of lipodystrophic features with myopathy, gastrointestinal dysmotility, skeletal abnormalities such as atlantoaxial instability and scoliosis, and arrhythmias.